Arc chute and shielding hood mounted on blade of high-voltage switch



Nov. 16, 1965 J. cs. DORSETT ARC CHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH 6 Sheets-Sheet 1 Filed Jan. 30, 1964 INVENTOR John G. Dorse'rr ATTORNEY MB/QXM Nov. 16, 1965 J. G. DORSETT 3,218,419

ARC GHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH Filed Jan. 30, 1964 6 Sheets-Sheet 2 Nov. 16, 1965 J. G. DORSETT 3,218,419

ARC GHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH Filed Jan. 30, 1964 6 Sheets-Sheet 3 $--J i Fig.4.

Nov. 16, 1965 J. G. DORSETT 3,218,419

ARC CHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH Filed Jan. 30, 1964 6 Sheets-Sheet 4 g 74 Q i 70 Nov. 16, 1965 J. G. DORSETT 3,218,419

ARC CHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH Filed Jan. 30. 1964 6 Sheets-Sheet 5 6lo f l S 6lb 63b k \znl F|g.l0.

(1 0 ||i X L O x Nov. 16, 1965 J. G. DORSETT 3,

ARC CHUTE AND SHIELDING HOOD MOUNTED ON BLADE OF HIGH-VOLTAGE SWITCH Filed Jan. 30, 1964 6 Sheets-Sheet 6 Fi g.!5.

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United States Patent C 3,218,419 ARC CHUTE AND SHIELDING HOOD MOUNTED N BLADE 0F HIGH-VULTAGE SWITCH John G. Dorsett, Bloomington, Ind., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., 21 corporation of Pennsylvania Filed Jan. 30, 1964, Ser. No. 341,329 13 Claims. (Cl. 200-446) This invention relates generally to switch constructions and, more particularly, to load-break switches suitable for disconnecting an associated circuit.

A general object of the present invention is to provide an improved switch construction suitable for effectively interrupting a circuit.

The problem of both interrupting and disconnecting a high-voltage power circuit at points where conventional power circuit breakers, such as oil circuit breakers, are impractical or uneconomical, involves a number of difficulties including those associated with the usual requirements "for simplicity and ruggedness in structure, compactness, economical construction and operation, and electrical efliciency in both interrupting the load power are and disconnecting the circuit. Although a considerable amount of design Work has been devoted to such a type of switch construction, the devices, in general, have been somewhat complicated and expensive, particularly for moderate interrupting duty, such as, for example, interrupting the magnetizing current of say, for example a 15,000-volt power transformer.

A principal object of the invention, therefore, is the provision of an improved load-break switch that is simple, rugged and inexpensive in construction, and that is capable of efficiently interrupting moderate load currents in high-voltage power circuits and disconnecting the power circuits.

Still another object of the present invention is the provision of a load-break disconnecting switch suitable for outdoor application, and with provision for shielding the auxiliary contact blade portion of the switch from inclement weather conditions.

Still a further object of the present invention is the provision of an improved load-break disconnecting switch in which a quick-break auxiliary arcing blade mechanism is associated with the stationary terminal of the switch. This has the advantage of minimizing the weight associated with the movable main blade bridging contact.

Another object of the present invention is the provision of an improved load-break disconnecting switch in which the auxiliary arc-chute device is secured to, and movable with the end portion of the rotatable main disconnecting switch blade.

Yet a further object of the present invention is the provision of an improved load-break disconnecting switch in which shielding hood means supports the auxiliary arc chute adjacent the end of the rotatable main disconnecting switch blade, and in which the shielding hood is preferably made of a conducting material so as to carry the current from the auxiliary contacts associated with the arc chute to the main disconnecting switch blade.

Still a further object of the present invention is the provision of an improved load-break disconnecting switch in which a pair of relatively movable auxiliary arcing contacts are associated in shunt relationship with the main disconnecting switch blade, and in which during the opening operation, both of the auxiliary contacts are movable to thereby assure high-speed quick-breaking action of the auxiliary arcing contacts. This has the important advantage of minimizing arcing and insuring the establishment of the are very quickly.

Yet a further object of the present invention is the provision of an improved load-break attachment device which may be readily secured to existing-type conventional disconnecting switches, so as thereby to increase their interrupting capacity.

Still a further object of the present invention is the provision of an improved load-break disconnecting switch in which a simplified type and highly effective latching ar rangement for the auxiliary contacts is provided.

An ancillary object of the present invention is the provision of an improved load-break disconnecting switch in which a highly effective latching and releasing means is provided by the use of different radius arms for the cooperating rotatable main contact blade and the r0 tatable quick-break auxiliary arcing blade.

Yet a further object of the present invention is the provision of an improved load-break disconnecting switch suitable for a medium voltage range of say, for example, 15 kv., 46 kv. and 69 kv. application.

According to one aspect of the present invention, a rotatable main disconnecting switch blade carries a spacedplate-type arc chute generally laterally thereof. Within the arc chute is secured a pair of inwardly-biased auxiliary arcing spring fingers, which are electrically connected to the end of the main disconnecting switch blade by means of a laterally-extending conducting shielding hood member, the latter being secured to the side of the end portion of the main disconnecting switch blade.

Cooperating with the inwardly-biased spring arcing fingers disposed interiorly of the arc chute carried by the main disconnecting switch blade is a quick-acting spring-biased auxiliary arcing contact blade pivotally mounted to a supporting portion of the main stationary contact assembly. Spring means, such as a helical torsion spring, is employed to bias the extremity of the auxiliary arcing blade in a direction away from the contacts carried by the arc chute. During the opening operation, the main disconnecting switch blade is rotated in an opening direction to first effect separation between the extremity of the main disconnecting switch blade and an associated stationary tongue-type main contact, while at the same time imposing tension upon the aforesaid helical biasing springs as the extremity of the auxiliary arcing blade is rotated, being carried along with the movable arc chute. Due to the difference in the radius arms of circular travel of the main disconnecting switch blade and the auxiliary quick-break arcing contact, at a predetermined point in the opening circular travel of the main disconnecting switch blade, the springbiased quick-break arcing blade pulls free of the moving contacts disposed within the movable arc chute and separates therefrom with a quick-break action. At this time thebreak distance between the main contacts is sufficient to prevent the establishment of an arc. The resulting arc established at the auxiliary contacts is extinguished within the slot provided by the spaced-plate arc chute, and the circuit is thereby interrupted. Continued opening rotatable travel of the main disconnecting switch blade inserts the usual isolating distance between the extremity of the rotatable main switch blade and the cooperating stationary main contact structure. The auxiliary blade retracts, due to spring action, and during a subsequent closing operation, the main contacts and the auxiliary contacts close substantially simultaneously.

Other objects of the invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiment thereof shown in the accompanying drawings, and it comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth, and the scope of the application of which is set forth in the appended claims.

For a more complete understanding of the nature and scope of this invention reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

FIG. 1 is an end elevational view of a three-pole loadbreak disconnecting switch incorporating features of the present invention, and the contacts being illustrated in the closed-circuit position;

FIG. 2 is a side elevational view of the improved loadbreak disconnecting switch taken substantially along the line 11-11 of FIG. 1, again the contact structure being illustrated in the closed-circuit position;

FIG. 3 is a top plan view of the improved load-break disconnecting switch of the present invention, the contact structure being illustrated in the closed position, and the View being enlarged to more clearly illustrate details of construction;

FIG. 4 is an enlarged side elevational view of one of the pole-units of the three-phase load-break disconnecting switch of the instant invention, taken from the other side of the switch than that illustrated in FIG. 2, and, additionally, taken substantially along the line IV-IV of FIG. 3;

FIG. 5 is a diagrammatic View illustrating the releasing action which takes place at a predetermined point in the opening rotative travel of the main disconnecting switch blade;

FIG. 6 is a detailed view of the auxiliary arcing blade;

FIG. 7 is a top plan view of the shielding hood structure;

FIG. 8 is a side elevation view of the shielding hood structure of FIG. 7;

FIG. 9 is a fragmentary view, partially in section, taken substantially along the line IXIX of FIG. 4;

FIG. 10 is a considerably enlarged sectional view of one of the auxiliary arcing contact blades taken substantially along the line XX of FIG. 11;

FIG. 11 is a side-elevational view of the auxiliary arcing contact blade of FIG. 10;

FIG. 12 is an end sectional View of the auxiliary arcing contact blade of FIG. 11, taken substantially along the line XIIXII of FIG. 11;

FIG. 13 is a top plan view of the stationary contact assembly;

FIG. 14 is a side elevational view of the stationary contact assembly of FIG. 13, with the auxiliary contact blade illustrated in its fully retracted position; and

FIG. 15 is an end elevational view of the stationary contact assembly.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a three-phase load-break disconnecting switch. As shown, the three-phase load-break disconnecting switch comprises a plurality of pole-units A, B, and C mounted in an upstanding manner upon a framework, generally designated by the reference numeral 2.

Preferably, the framework 2 includes an upstanding pole 3, and a clamping channel 4, secured by bolts 5, 6 to a side of the pole 3. Iutting laterally of the clamping channel 4 are support members 8, It with diagonally-extending bracing members 12, 14.

An interphase rotatable crank-shaft 16 is provided having a crank-arm 18 fixedly secured to it, as more clearly illustrated in FIG. 2 of the drawings. An operating link 20 is pivotally connected, as at 21, to the crankarm 18. The lower end of the operating rod 20 is fixedly secured to a rotatable bracket member 22, which, in turn, is rotated by a manual handle 23.

Operative rotation of the interphase crank-shaft 16 will effect rotative movement therewith of a plurality of crank arms 25, each of which is associated with one of the pole-units A, B or C. As shown more clearly in FIG. 2, the extremity of the crank-arms are pivotally connected as at 26, to the lower extremities of insulating operating rods 27, the latter preferably being formed of porcelain. As shown more clearly in FIG. 4 of the drawings, the upper extremity of the operating rod 27 is pivotally connected, as at 28, to a rotatable main disconnecting switch blade, generally designated by the reference numeral 30.

With particular reference to FIG. 3 of the drawings, it will be noted that the rotatable main disconnecting switch blade 30 comprises a pair of laterally-spaced individual switch blades 30a, 30b spaced laterally apart by spacing sleeves 31, which surround mounting bolts 32.

As shown more in detail in FIG. 4 of the drawings, the spaced individual disconnecting switch blades 30a, 30!) are pressed inwardly against the side faces of an upstanding tongue contact 33, which preferably forms an integral upstanding portion of a terminal casting 34. As shown in FIGS. 3 and 4, the terminal casting 34 includes an end terminal pad 35 having mounting apertures 36 disposed therein. A suitable line connection, not shown, may be fixedly secured in conductive relation to the terminal pad 35, as well known by those skilled in the art.

With further reference to FIG. 4 of the drawings, it will be noted that the terminal casting 34 is supported in an upstanding relation by means of a supporting insulator 29, the latter, in turn, being supported upon a channel support member 37. As shown in FIG. 2, the channel support member 37 is fixedly secured to the horizontally-extending mounting members 38, 39. Such members provide the function of attachment for dead end insulators 4t 41, maintaining the line connections 42, 43, in tension.

With reference to FIG. 3 of the drawings, it will be noted that the free end of the main disconnecting switch blade 30 engages a tongue contact 45, constituting an integral upstanding extension of a terminal casting 46, the latter also having a laterally-extending terminal-pad portion 47. Reference may be had to FIGS. 13 and 15 in this connection. The terminal casting 46, in turn, is supported upwardly of the channel support member 37 by a post-type insulator 48.

The upstanding tongue contact 45 of the terminal casting 46 constitutes a portion of a main relatively stationary contact structure, generally designated by the reference numeral 5%). As shown in FIG. 3, the tongue contact 45 of the main stationary contact structure 59 enters between the free ends of the individual switch blades 30a, 33b, wedging the latter apart and making good contacting connection therewith.

As well known by those skilled in the art, to separate the main disconnecting switch blade 30 from the stationary contact structure 5t), with no provision for extinguishing an are drawn therebetween, would soon quickly effect such an erosion of the several parts as to render the structure inoperative. To prevent the occurrence of such deleterious arcing, provision is made to quickly efifect the extinction of any established arcing. To effect this end, an auxiliary interrupting device, generally designated by the reference numeral 60, is provided. As shown more clearly in FIGS. 3 and 4 of the drawings, the auxiliary interrupting device 60 includes a spaced-plate-type arc chute 61 comprising a pair of spaced plates 61a, 61b together with an interposed movable auxiliary arcing contact structure, generally designated by the reference numeral 63. Such arcing contact structure 63, preferably assumes the form of a pair of inwardly-biased auxiliary contact blades or fingers 63a, 63]; secured, such as by riveting, to the opposite sides of a flange portion 70 of a shielding hood structure, generally designated by the reference numeral '7 11, and illustrated more clearly in FIGS. 7 and 8 of the drawings. Biasing springs 66 may be employed to bias the auxiliary contact blades or fingers 63a, 63b inward-1y, as shown in FIG. 9.

As shown more clearly in FIG. 3 of the drawings, the shielding hood structure 71 has an additional downwardly-extending flange portion '73, which is secured, such as by means of a pair of mounting bolts 75, to the side of one of the individual disconnecting blades b, as shown in FIG. 4. It will, accordingly, be apparent that the conducting shielding hood structure 71 not only provides a protection means against the weather for a quick-break actuating mechanism 80, more fully described hereinafter, but, in addition, also provides a lateral oifset support for the spaced-plate arc chute 61. In other words, when the load-break disconnecting switch of the present invention is in the closed-circuit position, as is illustrated in FIG. 4 of the drawings, it is desirable to prevent rain and sleet from directly contacting the operating means for the rotatable auxiliary arcing blade 90. For achieving this purpose, the hood structure 71, with its three downwardly-extending integral flange portions '70, 73 and 74, provides such protecting action against inclement weather conditions. 'In addition, the hood structure 71, being formed of metal, provides conducting means from the extremity of the main disconnecting switch blade 30 to the auxiliary movable contact structure 63.

FIGS. 13 and 14 more clearly illustrate the pivotal mounting of the auxiliary arcing blade 90. FIG. 6 illustrates the auxiliary arcing blade in detail. With particular reference being directed to FIG. 13 of the drawings, it will be noted that the terminal casting 46 has an angularly-extending spring support arm with a bifurcated end portion 102. The bifurcated end portion 102 of the supporting arm 100 has bight portions 102a, 102b, through which are provided pivot apertures 104, 105, through which passes a pivot mounting bolt 106 having a head portion 107 and a threaded stud portion 108. A slotted locking nut 109 is threaded over the stud portion 108, and preferably a cotterpin 1'12 passes therethrough to lock the nut and prevent the latters loosening.

As shown in FIG. 13, the auxiliary arcing blade 90 is pivotally mounted on the pivot bolt 106, and has laterally extending therefrom, such as by means of a riveted connection, a biasing pin designated by the reference numeral 1115. The other end of the biasing pin is preferably riveted over a relatively small support arm 130, having an aperture 131 extending therethrough. The pivot bolt 106 extends through the aperture 131 so as to provide a more stable pivotal mounting of the auxiliary arcing blade '90.

Surrounding the pivot bolt 106 and extending through the pivot apertures 104, 105 is a spring sleeve i135 having a helical torsion spring 136 coiled thereabout. One end 136a of the biasing spring bears against a horizontal flange portion 1020 of the terminal casting 46. The other end 1356b bears against a recess portion of the biasing pin 115, and urges the auxiliary arcing contact blade 90 in a clockwise direction with a force F, as viewed in FIG. 4 of the drawings. An adjustable stop bolt may be provided, as shown in FIG. 14, to limit the opening position of the rotatable auxiliary arcing blade 90.

In the closed-circuit position of the load-break disconnecting switch of the present invention, the main disconnecting switch blade 30 engages the main stationary contact structure '50, and, additionally, the movable auxiliary contact structure 63 engages the extremity 90a of the auxiliary arcing blade 90 making good contacting relation therewith.

During the opening operation, upward movement of the insulating operating rod 27 effects counterlockwise rotative opening travel of the movable disconnecting switch blade 30 about the pivot axis 33a thereof. Such opening rotative movement of the movable disconnecting switch blade 30 soon provides a separation between the extremity of the disconnecting switch blade 30 and the tongue contact 45 of the main stationary contact structure 50, the auxiliary arcing contact structure 92 remaining latched. In other words, during the initial portion of the opening operation, the extremity 90a of the movable auxiliary arcing blade 90 is latched between the inwardly-biased auxiliary contact blades or fingers 63a, 6312. Such separating action is illustrated in FIG. 5 of the drawings. At a predetermined point P in the opening rotative travel of the movable disconnecting switch blade 30, the radius arms R R are such, that upon passage through the horizontal distance D, as illustrated in FIG. 5, releasing action occurs between the auxiliary blade 90 and the auxiliary movable contact 63 cooperating therewith. Such releasing action at the point P effects a quick-break separation between such con tacts, aflorded by the biasing action exerted by the helical spring 136, and the resulting arc is established within the slot 64 between the spaced plates 61a, 61b of the arcchute structure 61. It will be noted that at the time of release, both auxiliary arcing contacts 63 and 90 move in opposite directions to provide thereby extremely fast contact separating movement, the blade 90 being rapidly retracted by the relatively strong spring 136. Rapid arc lengthening is thereby achieved.

Arc extinction soon occurs, which action results, in part, from gas evolution emitted by the inner faces of the insulating plates 61a, 61b of the arc chute 61. Preferably, t'he spaced plates 61a, 61b comprising the arc-chute structure 61, are made of a high-molecular-weight polyoxymethylene, such as set forth in US. Patent 3,059,081, issued October 16, 1962, to Gordon C. Gainer and Albert P. Strom, and assigned to the assignee of the instant invention. Such material is sold by the Du Pont Company under the trade name of Delrin. This material is ideal for this purpose because of its outstanding electrical and weather-resistant properties. Some of the properties of this material contributing to its success in this usage are its temperature resistance, high-fatique endurance, solvent resistance, form stability and moisture resistance, and high impact strength.

The volume resistivity of the present material is high and does not change appreciably due to moisture absorption. As a result, it maintains its good electrical properties under high humidity exposure, even after complete immersion in water.

Another outstanding ability of the present material is its non-tracking characteristics. Erosion of the surface is not noticeable even after 200 arc interruption operations at full interruption rating of the present apparatus. Loss of material is not noticeable and only a slight blacking of the surface is apparent.

The overall strength of the material, excellent insulating and tracking characteristics, and resistance to mois ture and temperature make the material ideal for electrical products subjected to severe weather conditions. Finally, the material produces gas under arcing conditions making it suitable for de-ionizing power arcs.

Although, as described hereinbefore, the arc-chute structure 61 is preferably formed of a high-molecularweight polyoxymethylene, nevertheless, good results may be achieved by other gas-evolving materials Well known to those skilled in the art. However, for outdoor application of the switch structure 1, the aforesaid highmolecular-weight polyoxymethylene material has proved to be of outstanding performance, not only as regards its weather-resistance properties, but also as regard to its arc-extinguishing characteristics.

The load-break disconnecting switch structure 1 of the present invention has given outstanding experimental performance. For a particular commercial application, a 400-ampere load-break rating at 15 kv. is a desirable commercial rating. However, it is to be clearly understood that the foregoing rating was given merely by way of example, and by a suitable proportioning of the parts, the voltage and ampere rating of the switch 1 could be increased to much higher values.

Since certain further changes can be made in the foregoing construction, and different embodiments of the invention can be made Without departing from the spirit and scope of the present invention, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said ro-. tatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switchblade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

2. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rtatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, means biasing said other movable auxiliary contact to a retracted position close to said second stationary main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch against the opposition afforded by said biasing means, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts and said other movable auxiliary contact will quickly move to its retracted position.

3. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means movable in a vertical plane, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed circuit position of the switch, the open end of the arc chute facing downwardly in the closed position of the switch, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

4. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed circuit position of the switch, said arc-chute being formed at least in part of a high-molecular-weight polyoxymethylene, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the loadbreak disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

5. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switchblade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means by a conducting hood member and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, said hood member electrically connecting said one auxiliary arcing contact to said blade means and at least partially shielding said second main contact means from the weather, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

6. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rot-atable main disconnecting switch-blade means, means pivotally mounting said rot-atable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts comprising a pair of latching contact fingers and being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being blade-shaped and movably mounted to said second main contact means and under the bias of spring means, a movable arc-chute attached to the free end of said blade means and enclosing said pair of latching fingers for weather protection in the closed-circuit position of the switch, and means providing a releasable latching engagement between said pair of latching fingers and the blade-shaped auxiliary contact during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxilary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts and then will quickly open due to the spring bias.

7. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contacts mounted upon spaced post-type insulators, a movable rotatable main disconnecting switch-blade, means pivotally mounting said rotatable switch-blade about said first main contact so as to have the free end of the rotatable blade make separable contacting engagement with said second relatively stationary main contact, a laterallydisposed auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade to one side thereof and the other of said movable auxiliary arcing contacts being movably mounted to one side of said second main contact, a movable arc-chute attached to the free end of said main disconnecting switch-blade and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, and means providing a quick-break releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main disconnecting switch-blade and said second main contact to prevent arcing to these parts.

8. A load-break disconnecting switch assembly including spaced relatively stationary first and sec-nd main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and electrically connected thereto and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means and electrically connected thereto, a movable narrow slot type of arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, and means providing a quick-break releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

9. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device to prevent arcing at the main contact means including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being movably mounted under bias of spring means to said second main contact means, a movable arc-chute attached to the side of the free end of said blade means and enclosing said one mov-able auxiliary arcing contact for weather protection in the closed-circuit position of the switch, and means providing a quick-break releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

10. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being pivotally mounted to said second main contact means, means biasing said other auxiliary arcing contact in the opposite rotative direction about said second main contact means from the direction of opening travel of said main blade means about said first main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed circuit position of the switch, and means providing a quick-break releasable latching engagement between said two movable auxiliary arcing contacts during the initial rotative opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

11. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switchblade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable spaced-plate type of arc-chute for enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, a flanged conducting shielding hood member for attaching said arc-chute to the free end of said blade means, and means providing a quick-break releasable latching engagement between said two mova ble auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

12. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts being carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, said second relatively stationary main contact means including a main stationary contact and a spring support spaced therefrom for pivotally mounting under spring tension said other auxiliary arcing contact, a shielding hood member interposed between said blade means and said are chute and serving not only to support the same but also to shield the spring support from the weather, and means including said spring support to provide a quick-break releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the load-break disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

13. A load-break disconnecting switch assembly including spaced relatively stationary first and second main contact means, a movable rotatable main disconnecting switch-blade means, means pivotally mounting said rotatable blade means about said first main contact means so as to have the free end of the rotatable blade means make separable contacting engagement with said second relatively stationary main contact means, said switch-blade means opening upwardly in a generally vertical plane, an auxiliary interrupting device including two separable auxiliary arcing contacts both of which are movable, one of said movable auxiliary arcing contacts be ing carried adjacent the free end of said rotatable main disconnecting switch-blade means and the other of said movable auxiliary arcing contacts being sickle-shaped and movably mounted to said second main contact means, a movable arc-chute attached to the free end of said blade means and enclosing said one movable auxiliary arcing contact for weather protection in the closed-circuit position of the switch, said arc-chute having the upper end thereof closed and at least portions of the two sides thereof closed so that when said sickle-shaped movable auxiliary arcing contact engages said one auxiliary arcing contact substantially complete weather protection is obtained, and means providing a releasable latching engagement between said two movable auxiliary arcing contacts during the initial opening operation of the loadbreak disconnecting switch, whereby said two movable auxiliary arcing contacts will not become released from their latching engagement until an adequate gap distance exists between the free extremity of the main blade means and said second main contact means to prevent arcing to these parts.

References Cited by the Examiner UNITED STATES PATENTS 1,796,361 3/1931 Desmond ZOO-48 2,571,864 10/195-1 Graybill 200-146 3,046,365 7/ 1962 Graybill 200-62 X 3,136,874 6/1964 Albright 200146 X KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K, SCHAEFER, Examiner. 

1. A LOAD-BREAK DISCONNECTING SWITCH ASSEMBLY INCLUDING SPACED RELATIVELY STATIONARY FIRST AND SECOND MAIN CONTACT MEANS, A MOVABLE ROTATABLE MAIN DISCONNECTING SWITCH-BLADE MEANS, MEANS PIVOTALLY MOUNTING SAID ROTATABLE BLADE MEANS ABOUT SAID FIRST MAIN CONTACT MEANS SO AS TO HAVE THE FREE END OF THE ROTATABLE BLADE MEANS MAKE SEPARABLE CONTACTING ENGAGEMENT WITH SAID SECOND RELATIVELY STATIONARY MAIN CONTACT MEANS, AN AUXILIARY INTERRUPTING DEVICE INCLUDING TWO SEPARABLE AUXILIARY ARCING CONTACTS BOTH OF WHICH ARE MOVABLE, ONE OF SAID MOVABLE AUXILIARY ARCING CONTACT BEING CARRIED ADJACENT THE FREE END OF SAID ROTATABLE MAIN DISCONNECTING SWITCHBLADE MEANS AND THE OTHER OF SAID MOVABLE AUXILIARY ARCING CONTACTS BEING MOVABLY MOUNED TO SAID SECOND MAIN CONTACT MEANS, A MOVABLE ARC-CHUTE ATTACHED TO THE FREE END OF SAID BLADE MEANS AND ENCLOSING SAID ONE MOVABLE AUXILIARY ARCING CONTACT FOR WEATHER PROTECTION IN THE CLOSED-CIRCUIT POSITION OF THE SWITCH, AND MEANS PROVIDING A RELEASABLE LATCHING ENGAGEMENT BETWEEN SAID TWO MOVABLE AUXILIARY ARCING CONTACTS DURING THE INITIAL OPENING OPERATION OF THE LOAD-BREAK DISCONNECTING SWITCH, WHEREBY SAID TWO MOVABLE AUXILIARY ARCING CONTACTS WITH NOT BECOME RELEASED FROM THEIR LATCHING ENGAGEMENT UNTIL AN ADEQUATE GAP DISTANCE EXISTS BETWEEN THE FREE EXTREMITY OF THE MAIN BLADE MEANS AND SAID SECOND MAIN CONTACT MEANS TO PREVENT ARCING TO THESE PARTS. 